Power-operated toothbrush



'June 26, 1945. E, TOMPKINS 2,379,049v

POWER-OPERATED TOOTHBRUSH Filed 'Jan. 1, 1944 INVENTOR- 7 4M ATTORNEYS? I2 has an endwise extending lug IIlb, (Fig. 4), which is received in an eccentric recess 3a (Fig. 5) in the adjacent end of the shaft 3. Because of the eccentricity of the stud I3 and the recess I2 with respect to the shafts 3 and I0, and the engagement of lug II'Ib in the recess 3a, therotation of the armature shaft 3 will cause rotation at the same speed of the shaft I II and simultaneously rock or oscillate the shaft I and its bearing within the passage 8, as shown for 'example by the dot and dash lines A and B in Fig. 3, which indicate the difference of position of the axes of the shaft I0 and the armature shaft 3.

' Thus, the armature shaft 3 will not only rotate the brush shaft I II at the same speed, but also cause bodily gyration of the free or outer end of shaft ID in a small, closed loop path.

The outer end of the shaft I0 is provided with a non-circular recess I which receives a noncircular end of the twisted wire shank I6 of a suitable brush H which carries bristles I8. Brushes of this type are well known in the art and the bristles may be arranged in small groups or they may be formed in a sort of spiral or helical row in the twisted wire shank. The shank I6 is snugly received in the recess I5 so that rotation of the shaft ID will cause similar rota tion of the brush I'I. Likewise the rocking of the shaft I0 simultaneously with its rotation will be transmitted to the brush I'I. Thus, while the handle I is held in ones hand, with the motor running, the rotary and bodily gyrating brush I6 may be applied to the teeth with suitable water and tooth paste or tooth powder, so as to thoroughly and quickly clean the teeth.

Power driven brushes heretofore have not become popular, owing to the fact that when such a rapidly moving brush engages the gums of the teeth or the inside of the cheeks which overlies the teeth, serious scratching or injuries to the tissues of the mouth occur, with resulting danger of infection. It is highly desirable that the brushing be confined as fully as possible to the teeth alone and not to surrounding tissue. Accordingly, in accordance with this invention, a uard I9 is provided with a reduced end 20 which' slidingly telescopes over the outer end of the tubular element 5'so as to slide endwise thereon. The remainder of the guard is larger in diameter or crosswise dimensions than the element 5, so that the guard may, when desired, be slid fully into the dash line position shown in Fig. 3, in which the outer end of the guard is then approximately alined with the outer end of the element 5. This exposes all of the bristles of the rotary brush around the entire periphery of the brush. Such a. brush may then be held under the faucet for rinsing or it may be swished in soap suds and then rinsed in order to fully dislodge all foreign matter and render it clear for subsequent use.

The guard I9 may then be slid back into the full line position shown in Fig. 3. This guard I9 comprises more than half of a cylinder in the portion where it is coextensive in length with the bristle-carrying portion of the brush shank H, but is not a complete cylinder, so that the guard, in effect, has an open window 2I along one side thereof in length coextensive with the bristle-carrying portion of the brush. Because of this, the bristles I8 may project slightly through this window, as shown in Fig. 3. When such a rotating brush is applied to the teeth, thehandle I is so held that the window 2| will approach the teeth, with the brush projecting to engage the teeth. The guard, which otherwise surrounds the rotating brush, will prevent contact of the rotating brush with the gums or with the cheek tissues which normally abut against the teeth or the gums. There is thus no injury to the tissues of the mouth, and there is also nothing to prevent full application of the rotary and gyrating brush to all of the exposed surfaces of the teeth. The device is thus perfectly safe to use, yet the guard can be quickly shifted endwise into the dash line position for cleaning. The part- 20 of the guard I9, which slides on the tubular part 5, may be split endwise, if desired, so as to frictionally grip the part 5, thus providing a simple way of holding the guard I9 in either of its two positions shown.

When the brush is not in use, the set screw "I may be backed off slightly to release the tubular element 5. The latter may then be detached from the handle, which enables the detached end to be disposed alongside the handle I, thus greatly cutting down the overall dimensions of the case in which such devices can be packed. The device can be quickly reassembled, as shown in Figs. 1 to 3, by reversing the steps. The brush I6 can also be detached from the recess I5 for replacement when necessary, or different individuals can use the handle and tubular element and merely substitute their own individual brush IS in the recess I5 and then remove it after use.

In Fig; 6, the construction is generally similar to that shown in Figs. 1 to 5, and similar parts are given similar reference characters, but the detachable coupling between the armature shaft 3 and the brush shaft III has been replaced by a different type of coupling. This shaft 3 is provided with an eccentric pin 22, which is noncircular in shape, as shown in Fig. 5, and the shaft I0 similarly has an eccentric end pin 23 of non-circular shape. These eccentrically located pins are received in recesses provided in opposite ends of a flexible coupling element 24. This flexible element 24 is preferably of flexible, molded rubber which flexes with sufficient freedom to conform to the rockings of the shaft III, yet is sufficiently rigid to provide a drive between the shafts 3 and I0. When the tubular element 5 is detached from the handle I, the coupling element 24 slides off the pin 22 on the end of the armature shaft 3,'and when the device is reassembled, as shown in Figs. 4. and 5, the coupling element 24 is slid over the pin 22 to reconnect the shafts 3 and I0.

In Fig. 8, the guard 25, which corresponds to the guard I9 of Figs. 1 to '7, is formed of molded rubber which is flexible yet with the consistency of ordinary rubber tubing, and the sides of the guard which provide the open window through which the bristles I8 may project are provided with small, tapered, pin-like projections 26 which, while flexible with reasonable freedom, have a tendency to return to their normal, upright positions, as shown in Fig. 6. When a guard of this type is applied around the moving brush, the engagement of the flexible rubber prongs 26 with the gums before the bristles engage the gums, will aid one in knowing when to stop the up and down movements of the brush, and thus prevent movement of the rapidly moving bristles against the ums. This guard 25 maybe slid endwise 0n the tubular element 5, the same as the guard I9 in Figs. 1 to 5. Rubber products of this type are known as molded rubber, and the flexibility is approximately the same as that of rubber tubing or water bags, which are not only flexible, but normally are self-shape-retaining.

In the use of a brush of this type, the motor is started in operation and the handle I grasped in the hand. The guard I9 or 25 is shifted into its protective position shown in full lines in the drawing, and suitable tooth paste or powder is applied to the moving bristles. The brush is then applied to the exposed tooth surfaces and moved slowly up and down along the rows of teeth, both inside and out faces, until the desired cleaning action on the teeth is obtained. This guard prevents injury to the mouth tissues, and because of the rapidly moving bristles a more effective brushing is obtained with a minimum of physical effect. Because of the spiral arrangement of thebristles, all of the surfaces of the teeth receive adequate brushing, and the bristles also can more effectively penetrate into the cracks and spaces between the teeth and dislodge food particles therefrom. Not only is there the cleaning action on the teeth, due to the rotating bristles,

but also the gryratory movement of the bristlecarrying end of the brush, of high frequency but of small amplitude impart to the teeth and through the teeth to the gums a slightly gyratorymassage or movement which stimulates blood circulation through the gums, and thus tends to reduce infections and produce a more healthful condition of the teeth and gums.

While the brush illustrated is one formed of bristles projecting from a base, the word brush is intended to include within its scope and meaning, and as an equivalent of a bristle-carrying element, any other rotary cleaning element such as, for example, a cylinder of soft, resilient and flexible natural or synthetic rubber, preferably with small integral and radially extending, flexible projections on its periphery to engage in irregu- -1arities and depressions of the teeth and between the teeth. The synthetic rubbers include these rubber substitutes which have properties that closely approach those of natural rubber. These synthetic rubbers have various names, some being popularly known as neoprene, chloroprene, buna S, and buna N.

It will be understood that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. A power operated tooth brush comprising a hollow handle, an electric motor within said handleand having a rotatable armature, a tubular element detachably connected to and extending from said handle, a shaft extending through said element and at its inner end eccentrically and detachably coupled to said armature to be rotated thereby, a bearing through which said shaft extends and which rotatably supports said shaft, the periphery of said bearing being convex and within and rockably fitting the bore of said element, adjacent its outer end, whereby said shaft may rotate freely as driven by said armature and also rock, with its bearing, universally in said element, and tooth cleaning means carried on the outer end portion of said shaft for rotation thereby and also simultaneously gyrating bodily in a small, closed-loop path.

2. A power operated tooth brush comprising a hollow handle, an electric motor within said handle and having a rotatable armature, a tubular element connected to said handle and extending therefrom, a bearing disposed within said tubular element adjacent its outer end, resilient means interposed between said bearing and the interior of said element and mounting said bearing for a 

